Speed control apparatus for hot gas engine

ABSTRACT

A speed control regulator for a closed-cycle displacer type hot gas engine comprising a separate heating device situated between the regenerating device and the hot end of the displacer cylinder, a passageway bypassing the heating device by leading directly from the regenerating device into the hot end of the displacer cylinder, an externally controlled variable valve which determines what portion of the working gas, if any, will bypass the heating device when being transferred into the hot end of the displacer cylinder, and nonvariable valves which allow all of the working gas to bypass the heating device when being transferred out of the hot end of the displacer cylinder. The hot end of the displacer cylinder is provided with insulation, becoming a mere repository for hot gas, as opposed to an externally heated adjunct to the heating device, in order to obtain rapid regulator response over a wide range of engine speeds. The total mass of gas within the engine&#39;&#39;s working chambers may remain constant at all speeds.

United States Patent [191 Ross [54] SPEED CONTROL APPARATUS FOR HOT GASENGINE [76] Inventor: Melvin Andrew Ross, 37 West Broad, Suite 630,Columbus, Ohio 43215 [22] Filed: Jan. 12, 1972 [21] Appl. No.: 217,314

[52] US. Cl ..60/24 [51] Int. Cl ..F02g 1/06 [58] Field of Search..60/24 [56] References Cited UNITED STATES PATENTS 334,153 1/1886Babcock ..60/24 3,630,022 9/1969 Jubb ..60/36 FOREIGN PATENTS ORAPPLICATIONS 151,683 9/1920 Great Britain ..60/24 PrimaryExaminer-Martin P. Schwadron Assistant Eran iner Allen M. OstragerAttorneyM. Andrew Ross [451 Apr. 3, 1973 [57] ABSTRACT A speed controlregulator for a closed-cycle displacer type hot gas engine comprising aseparate heating device situated between the regenerating device and thehot end of the displacer cylinder, a passageway bypassing the heatingdevice by leading directly from the regenerating device into the hot endof the displacer cylinder, an externally controlled variable valve whichdetermines what portion of the working gas, if any, will bypass theheating device when being transferred into the hot end of the displacercylinder, and nonvariable valves which allow all of the working gas tobypass the heating device when being transferred out of the hot end ofthe displacer cylinder. The hot end of the displacer cylinder isprovided with insulation, becoming a mere repository for hot gas, asopposed to an externally heated adjunct to the heating device, in orderto obtain rapid regulator response over a wide range of engine speeds.The total mass of gas within the engines working chambers may remainconstant at all speeds.

7 Claims, 4 Drawing Figures PATENTEUAPRB m5 3.724.206

SHEET 2 [IF 2 Fig.2

SPEED CONTROL APPARATUS FOR IIOT GAS ENGINE BACKGROUND OF THE INVENTIONThis invention relates to a means of regulating the speed and power of aclosed cycle displacer type hot gas engine.

Various solutions to the problem of speed and power regulation in suchengines have been suggested before. In some designs regulation has beenaccomplished by variation of the average pressure, and thus the mass, ofthe gas within the engines working chambers. This method is efficientbut involves cumbersome re-compressing equipment and storage tanks, aswell as a complicated valve system. Considerable weight is thus added tothe engine. Other designs maintain a constant average pressure butchange the phase angle of the displacer and power pistons, or increasethe dead space volume by communicating the power cylinder with anotherchamber. These last described methods can also be complex, and theygenerally decrease thermal efficiency.

The primary aim of this invention is to provide a simple, efficient, andlightweight regulator system for the closed-cycle displacer type hot gasengine, which will enhance the suitability of this type of engine forvehicular and other portable uses.

Other aims, features, and advantages will be apparent in thedescription, below.

SUMMARY OF INVENTION This invention is a speed regulator for aclosed-cycle hot gas engine of the displacer type. The total mass of gaswithin the working chambers of the engine may remain constant at alltimes. Speed is regulated by regulating the heat transferred to theworking gas during any complete working cycle. Heat transfer iscontrolled by varying the portion of working gas that passes through theseparate heating device of the engine. A passageway is provided whichbypasses the heating device by directly connecting the hot end of theregenerating device with the hot end of the displacer cylinder. The flowof working gas through this passageway is varied by an externallycontrolled variable valve.

BRIEF DESCRIPTION OFTHE DRAWINGS FIG. 1 is a schematic diagram of a hotgas displacer type engine constructed in accordance with this invention.

FIG. 2 is a detailed sectional view of the basic parts of the invention.

FIG. 3 is a bottom view of the valve body illustrated in FIG. 2.

FIG. 4 is a view of the combined variable nonvariable valve.

DESCRIPTION OF THE PREFERRED EMBODIMENT This invention is applicable toa closed-cycle hot gas engine of the displacer type. In one example ofsuch an engine the displacer piston moves a mass of working gas from thecool end of the displacer cylinder, where it has been compressed by thepower piston, through a cooling device, a regenerating device, and aheating device, and then into the hot end of the displacer cylinder. Thepower piston then expands the nowheated working gas and in this processsome of the heat is converted into mechanical energy. The displacerpiston then moves the gas back through the heating device, regeneratingdevice, and cooling device into the cool end of the displacer cylinderand the cycle is completed.

The heating device can be a set of passageways with a large surfacearea/volume ratio, such as a set of small tubes, heated by a burner. Theregenerating device can be a suitable passageway filled with smalldiameter steel wire, or other material, whichcan absorb and store heatfrom the gas as it passes through in on direction and transfers the heatto the gas as it passes through at a lower temperature in the-otherdirection. The cooling device can be a set of passageways with a largesurface area/volume ratio cooled by a water jacket.

According to the invention, the total mass of gas within the engine'sworking chambers may be maintained at a constant level. Unlike the usualhot gas engine design, all external heat is added to the gas in theheating device; the hot end of the displacer cylinder is merely aninsulated storage space for hot gas. A short passageway leading from theregenerating device directly into the hot end of the displacer cylinder,thus bypassing the heating device, is provided. A variable valve,externally controlled, situated between the regenerating device, theheating device, and this passageway, determines what portion of theworking gas will bypass the heating device when the displacer istransferring the gas to the hot endof the displacer cylinder.

By thus controlling the mass of gas that is passed through the heatingdevice during any engine revolution, and by further providing that heatis transferred into the gas only in the heating device, the variablevalve can control the heat input, and thus the power output, of theengine over a wide range of speeds.

The linkage operating the variable valve which is the speed controllercan also control the burner output, through obvious means, so the burnerwill supply less heat as more of the working gas bypasses the heatingdevice. The heating device will therefore be maintained at a nearlyconstant temperature. Other obvious means, such as a thermostaticcontrol, could also be used to maintain this constant temperature in theheating device.

Use of an insulated displacer cylinder hot end avoids the lag in engineresponse to a change in the variable valve setting that would beexpected were the hot end externally heated by the engines burner. Thislag would result from two facts: That a displacer cylinder hot end isnecessarily a large mass of metal in relation to its heat transferability, and that the mass of gas flowing into the hot end remainsconstant although its average temperature varies with the setting of thevariable flow valve. Were the valve setting changed to lower enginespeed, the burner would put out less heat and the average temperature ofthe gas entering the hot end would be reduced, but the hot end itself,due to its mass/heat transfer ratio, would take some time to reach a newequilibrium temperature. Engine speed would continue to decelerate untilthis new equilibrium temperature was established.

A similar lag would be expected upon engine acceleration because of thetime required for the displacer cylinder hot end to reach a new, highertemperature. The heating device itself would not be subject to thisproblem because it is being readily maintained at a nearly constanttemperature, as explained above.

The use of an insulated displacer cylinder offers the additionaladvantage of allowing a wider range of speed control. Since the variablevalve can readily bypass substantially all of the gas flowing into thehot end of the displacer cylinder around the heating device, it cancontrol a very wide range of heat input to the engine when, as in thisinvention, all heat input occurs in the heating device. However, werethe hot end of the displacer cylinder also heated by the burner, theheat added to the working gas by heat transfer in this cylinder wouldremain nearly constant at all times (except for the slow effect ofchanges in burner output, as mentioned in the preceding paragraphs) andbeyond the control of the variable valve, thus limiting the speed rangecontrolled by the valve.

In a design requiring an insulated hot end for the displacer cylinderand a direct bypass passageway between the hot end of the regeneratingdevice and the hot end of the displacer cylinder, it is at onceadvantageous and convenient to modify the usual hot gas engine gas flowpattern. It would be needlessly wasteful of engine power to force theexpanded, hence cooled, gas from an insulated displacer cylinder backthrough the high flow resistance of the heating device, only to pick upheat that would be immediately thereafter lost to the regeneratingdevice, when a short, direct passageway already exists between thedisplacer cylinder and the regenerating device, suitable fortransferring all the gas outof the hot end of the displacer cylinder.Not only'can the flow resistance of the heating device be avoided byusing this passageway, but flow resistance can also be reduced in theregenerating device because it can be made smaller, having less heat tostore.

The desired flowpattern can be provided by use of nonvariable valvemeans interposed between the heating device, the regenerating device,and the passageway. This nonvariable valve means can direct all the gasthat is moving toward the hot end, and that is not already leaked intothe passageway by the variable valve, through the heating device; and itcan direct all gas flowing out of the hot end through the passageway.

The invention will be explained more fully with reference to theaccompanying drawings, which represent one example thereof.

In FIG. 1, the displacer piston 3, divides the displacer cylinder intoan insulated hot end, 5, and a cool end, 33. The power piston, 1, isshown operating in a separate cylinder, but this is for clarity only,and the invention is equally applicable to engines where both thedisplacer piston and the power piston operate in the same cylinder. Theheating device, 9, connects the hot end of the displacer cylinder, 5,with the valve body, 13. A passageway, 7, also connects the hot end ofthe displacer cylinder with the valve body, 13, bypassing the heatingdevice, 9. The lower portion of the valve body is connected to theregenerating device, 23. The cooling device, 25, is connected to thelower end of the regenerating device and the cool end of the displacercylinder, 33.

The valve body, 13, contains the variable valve, 19, which is shown asacombined annular poppet/rotary face valve. In fact, valve 19 as shownis a dual purpose valve: It functions as the variable valve controllingthe engine speed, and also as one of the two nonvariable valves requiredto assure that all the gas bypasses the heating device when beingtransferred from the hot end to the cool end of the displacer cylinder.The combination of these two functions in one valve is not at allessential to this invention, but it does simplify the design, and forthat reason is preferred.

In its function as the variable valve, valve 19 performs when seated asa rotary face valve. FIGS. 3 and 4 best shows this function. Its rotaryposition can be controlled by providing a sliding splined connectionwith valve rod 27, the rotary position of which can in turn beexternally controlled by obvious means. The means shown as one examplein FIG. 1 is a splined adjuster cap, 31, which fits over a splinedportion of the valve rod, 27, and which can be externally rotated. Dualgeared crankshafts, 29, together with a scotch yoke reciprocatingmechanism, 30, allow the valve rod to be so controlled by its bottomextremity.

In its function as one of the two nonvariable valves, valve 19 performsas an annular poppet valve, actuated vertically by valve rod 27, whichis itself actuated by eccentrics on the crankshafts. The othernonvariable valve, 11, is shown as a circular poppet vale actuated bythe same valve rod. The valve rod, 27, has an increased diameter betweenvalves 19 and 1 1, better seen on FIG. 2, which allows both valves to beseated when said rod is in the center of its travel, but whichimmediately opens valve 11, or valve 19, as it moves above or below itscenter of travel, respectively.

Referring again to FIG. 1, the operation of an engine with the speedregulator apparatus is as follows: Beginning with the displacer piston,3, at the top of its stroke, and the power piston, 1, completing itscompression stroke, valve rod 27 .moves upward, opening nonvariablevalve 11. The displacer piston, 3, moves downward forcing the gas fromthe cool end, 33, through cooling device 25, through regenerating device23, through the open central portions 21 of valve 19, thence through theopen portions of central chamber 17 of valve 7 body 13, aroundnonvariable valve 11, through heating device 9, and into the hot end ofthe displacer cylinder, 5.

As the gas flows through the open central portions 21, of valve 19, anddepending upon the rotary position of valve 19, a variable amount of gaswill be leaked directly into annular chamber 15, thence it will passthrough passageway 7, into hot end 5. The larger the amount of gas thatis thus allowed to bypass the heating device, the lower the engine speedand power.

The flow pattern remains as described until the displacer piston, 3,reaches the bottom of its stroke. By this time the power piston, 1, iscompleting its expansion stroke, and the gas, which is almost entirelyin the hot end of the displacer cylinder or its extension over the powerpiston, is expanded and somewhat cooled. The valve rod, 27, then movesdownward, closing nonvariable flow valve 11, and opening valve 19. Asthe displacer piston moves upward it forces all the gas from hot end 5,through'passageway 7, into annular chamber 15, around the now-openedvalve 19, through the regenerating device 23, through the cooling device25, and into cool end 33, thus completing the cycle.

FIGS. 2 and 3 illustrate the valve body and valves in greater detailthan FIG. 1. Number references are identical with FIG. 1, with severaladditional references.

In FIG. 3, which shows the valve body from the bottom, with valve 19 andthe valve rod 27 removed, the blocked portion 35, of annular chamber canbe clearly seen. The blocked portions 37 of central chamber 17 can alsobe seen. The illustrated surfaces of the blocked portions of bothchambers are flush with the annular chamber valve seats, 45, for vvalve11. When valve 11 is seated, the blocked portions of both chambers canform a seal with corresponding portions of valve 19.

FIG. 4 shows combination annular poppet/rotary face valve 11, includingthe blocked central portions, 39; the open central portions, 21; theouter sealing portions, 41; and the outer relieved portions, 43.

Comparing FIGS. 3 and 4 it will be seen how valve 11 functions as thevariable valve when it is seated on valve body 13. In one position, theouter sealing portions, 41, of the valve completely seal thecorresponding open portions of annular chamber 15. At the same time theopen central portions, 21, of the valve leave completely unobstructedthe open portions of the central chamber, 17, of the valve body. Thisposition represents maximum engine speed and power, since all gas goinginto the hot end of the displacer cylinder is being directed through theheating device.

By rotating the valve against the valve body in either direction, openportions of annular chamber, 17, are exposed by outerrelieved portions,43, of the valve. At the same time, blocked central portions, 39, of thevalve cover a proportional part of the open portions of central chamber,17, of the valve body. After 90 of rotation, the open portions ofannular chamber, 15, will be completely exposed and the open portions ofcentral chamber, 17, will be completely blocked, in which case theengine will be stopped since all the gas is bypassing the heatingdevice.

What I claim is:

1. A speed control apparatus for a hot gas engine of the type which hasa displacer piston operating in a gas filled displacer cylinder having ahot end and a cool end, and which has a cooling device connected at itsfirst end to the cool end of said displacer cylinder and at its secondend to the first end of a regenerating device, said regenerating deviceconnected at its second end to the first end of a heating device, andsaid heating device connected at its second end to the hot end of saiddisplacer cylinder, so that said cooling device, regenerating device,and heating device together provide a passageway for said gas to betransferred by said displacer piston from one end of said displacercylinder to the other end, said speed control apparatus comprising:

a. Passageway means, situated so as to connect the hot end of thedisplacer cylinder and the second end of the regenerating device, forputting the hot end of said displacer cylinder in direct communicationwith the second end of said regenerating device, thus providing a gasflow path bypassing said heating device, and,

b. Variable valve means, situated at said passageway means, forcontrollably varying the gas flow resistance through said passagewaymeans, by which a portion of the gas flowing from the cool end of thedisplacer cylinder to the hot end of said cylinder can be variably andcontrollably diverted from said regenerating device through saidpassageway means directly into the hot end of said displacer cylinder,bypassing said heating device.

2. A speed control apparatus, as recited in claim 1, where the variablevalve means further comprises means, situated at said heating device,for controllably varying the gas flow resistance through said heatingdevice.

3. A speed control apparatus as recited in claim 2, where there isadditionally provided insulation means positioned at the walls of thehot end of the displacer cylinder, for reducing the heat transfer intoor out of said hot end, by which said hot end becomes a mere repositoryfor hot gas, as distinguished from a device in which additional heat istransferred to said gas.

4. A speed control apparatus, as recited in claim 3, where there isadditionally provided nonvariable valve means, situated between saidregenerating device and said passageway means, alternately opening andclosing said passageway means to gas flow but operating independently ofsaid variable valve means, by which gas flowing from the cool end of thedisplacer cylinder to the hot end of said cylinder is directed throughthe heating device when said nonvariable valve means is in the closedposition, and by which gas flowing from the hot end of the displacercylinder to the cool end of said cylinder may pass through saidpassageway means when said nonvariable valve means is in the openposition.

5. A speed control apparatus, as recited in claim 3, where there isadditionally provided nonvariable valve means situated between saidregenerating device, said heating device, and said passageway means,alternately opening and closing said passageway means and said heatingdevice to gas flow but operating independently of said variable valvemeans, by which gas flowing from the cool end of the displacer cylinderto the hot end of saidcylinder is directed through said heating device,and by which gas flowing from the hot end of the displacer cylinder tothe cool end of said cylinder is directed through said passageway means,bypassing said heating device entirely.

6. A speed control apparatus, as recited in claim 5, in which thenonvariable valve means comprises:

a. A valve body having a central cylindrical chamber in communicationwith the regenerating device and the heating device, with a valve seatin said cylindrical chamber, and having a concentric annular chamberopening at one end toward said regenerating device with valve seats atsaid open end, said annular chamber in communication with saidregenerating device and said passageway means, and A circular poppetvalve situated in said valvebody so as to seal the valve seat in thecentral cylindrical chamber of said valve body when the gas pressure inthe heating device is greater than that in the regenerating device, andY c. An annular poppet valve situated in said valve which seal theannular chamber of the valve body,

body so as to seal the valve seats in the Concentric annular chamber ofsaid valve body when the gas pressure in the regenerating device isgreater than that in the passageway means, and

(1. Valve actuating means for opening and closing said poppet valves inaccordance with the movement of the displacer piston.

for allowing gas to pass through the relieved portions of said valvewhen seated, and

d. Annular poppet valve blocking means, situated in the central portionof said valve, for providing a face seal with the central chamberblocking means when said valve is seated, said annular poppet valveblocking means arranged in relation to said relief means in such a wayso that, when said annular poppet valve is seated and rotated about itscentral axis, the gas passage area between the cen- 7. A speed controlapparatus, as recited in claim 6, in which the variable valve meanscomprises: lo

a. Annular chamber blocking means situated in and filling portions ofthe open end of the annular chamber in the valve body, for providing aface seal with any corresponding portions of the annutral chamberblocking means and the annular poppet valve blocking means decreases asthe gas passage area between the annular chamber lar poppet valve whensaid valve is seated, and flocking "l and the annular P pp Valve b.Central chamber blocking means situated in and lief lncl'eases,and

filling portions of the central cylindrical chamber Rotatfon means forcommumg F fy Posmon of the valve body, for providing a face seal with of5314 annular P pp valve relatlon to the any corresponding portions ofthe annular poppet valve P and h annular a central cllamber vaive whensaid valve is seated and blocking means, independently of the seatingand c. Annular poppet valve relief means, situated in the unseatmg ofSam annular P pp Valveouter sealing portions of the annular poppet valve

1. A speed control apparatus for a hot gas engine of the type which hasa displacer piston operating in a gas filled displacer cylinder having ahot end and a cool end, and which has a cooling device connected at itsfirst end to the cool end of said displacer cylinder and at its secondend to the first end of a regenerating device, said regenerating deviceconnected at its second end to the first end of a heating device, andsaid heating device connected at its second end to the hot end of saiddisplacer cylinder, so that said cooling device, regenerating device,and heating device together provide a passageway for said gas to betransferred by said displacer piston from one end of said displacercylinder to the other end, said speed control apparatus comprising: a.Passageway means, situated so as to connect the hot end of the displacercylinder and the second end of the regenerating device, for putting thehot end of said displacer cylinder in direct communication with thesecond end of said regenerating device, thus providing a gas flow pathbypassing said heating device, and, b. Variable valve means, situated atsaid passageway means, for controllably varying the gas flow resistancethrough said passageway means, by which a portion of the gas flowingfrom the cool end of the displacer cylinder to the hot end of saidcylinder can be variably and controllably diverted from saidregenerating device through said passageway means directly into the hotend of said displacer cylinder, bypassing said heating device.
 2. Aspeed control apparatus, as recited in claim 1, where the variable valvemeans further comprises means, situated at said heating device, forcontrollably varying the gas flow resistance through said heatingdevice.
 3. A speed control apparatus as recited in claim 2, where thereis additionally provided insulation means positioned at the walls of thehot end of the displacer cylinder, for reducing the heat transfer intoor out of said hot end, by which said hot end becomes a mere repositoryfor hot gas, as distinguished from a device in which additional heat istransferred to said gas.
 4. A speed control apparatus, as recited inclaim 3, where there is additionally provided nonvariable valve means,situated between said regenerating device and said passageway means,alternately opening and closing said passageway means to gas flow butoperating independently of said variable valve means, by which gasflowing from the cool end of the displacer cylinder to the hot end ofsaid cylinder is directed through the heating device when saidnonvariable valve means is in the closed position, and by which gasflowing from the hot end of the displacer cylinder to the cool end ofsaid cylinder may pass through said passageway means when saidnonvariable valve means is in the open position.
 5. A speed controlapparatus, as recited in claim 3, where there is additionally providednonvariable valve means situated between said regenerating device, saidheating device, and said passageway means, alternately opening andclosing said passageway means and said heating device to gas flow butoperating independently of said variable valve means, by which gasflowing from the cool end of the displacer cylinder to the hot end ofsaid cylinder is directed through said heating device, and by which gasflowing from the hot end of the displacer cylinder to the cool end ofsaid cylinder is directed through said Passageway means, bypassing saidheating device entirely.
 6. A speed control apparatus, as recited inclaim 5, in which the nonvariable valve means comprises: a. A valve bodyhaving a central cylindrical chamber in communication with theregenerating device and the heating device, with a valve seat in saidcylindrical chamber, and having a concentric annular chamber opening atone end toward said regenerating device with valve seats at said openend, said annular chamber in communication with said regenerating deviceand said passageway means, and b. A circular poppet valve situated insaid valve body so as to seal the valve seat in the central cylindricalchamber of said valve body when the gas pressure in the heating deviceis greater than that in the regenerating device, and c. An annularpoppet valve situated in said valve body so as to seal the valve seatsin the concentric annular chamber of said valve body when the gaspressure in the regenerating device is greater than that in thepassageway means, and d. Valve actuating means for opening and closingsaid poppet valves in accordance with the movement of the displacerpiston.
 7. A speed control apparatus, as recited in claim 6, in whichthe variable valve means comprises: a. Annular chamber blocking meanssituated in and filling portions of the open end of the annular chamberin the valve body, for providing a face seal with any correspondingportions of the annular poppet valve when said valve is seated, and b.Central chamber blocking means situated in and filling portions of thecentral cylindrical chamber of the valve body, for providing a face sealwith any corresponding portions of the annular poppet valve when saidvalve is seated, and c. Annular poppet valve relief means, situated inthe outer sealing portions of the annular poppet valve which seal theannular chamber of the valve body, for allowing gas to pass through therelieved portions of said valve when seated, and d. Annular poppet valveblocking means, situated in the central portion of said valve, forproviding a face seal with the central chamber blocking means when saidvalve is seated, said annular poppet valve blocking means arranged inrelation to said relief means in such a way so that, when said annularpoppet valve is seated and rotated about its central axis, the gaspassage area between the central chamber blocking means and the annularpoppet valve blocking means decreases as the gas passage area betweenthe annular chamber blocking means and the annular poppet valve reliefmeans increases, and e. Rotation means for controlling the rotaryposition of said annular poppet valve in relation to the valve body andthe annular and central chamber blocking means, independently of theseating and unseating of said annular poppet valve.